Aircraft safety switch



Mam}! 1957 J. F. HEALY AIRCRAFT SAFETY SWITCH 2 Sheets-Sheet l iwaw. A L i Filed Oct. 15, 1953 ATTORNEYS,

' March 26, 1957 J HEALY 2,786,912

AIRCRAFT SAFETY SWITCH Filed 001:. 15, 1953 2 Sheets-Sheet 2 n Y g ATTORNE$ United States Paton t i AIRCRAFT SAFETY SWITCH Joseph F. Healy, Wcstport, C0nn., assignor t0 Harvey Huhhell, Incorporated, Bridgeport, Come, a corporation of Connecticut Application October 15, 1953, Serial No. 386,162

11 Claims. (Cl. ZOO-67) This invention relates to an aircraft safety switch, and has for an object to provide an improved switch construction which may be used as a main switch for controlling the source of current, that is, may be used for turning on and off the current from the battery'to various electrical devices such as lights, starter, instruments and so forth, on an airplane, and at the same time make or break the generator circuit. In other words, in which both the battery circuit and the generator circuit are made or broken at the same time.

Another object is to provide a switch for controlling the generator and battery circuits in which, if, for example, a fire starts on the plane, by throwing this switch the battery, and the high tension system and so forth, may be immediately isolated to assist in avoiding spreading of the fire.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawings forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In these drawings:

Fig. l is a longitudinal section substantially on line 11 of Fig. 2, with the switch in the closed position but with the cover plate and free end portion of the movable switch assembly shown in side elevation;

Fig. 2 is a bottom plan view looking toward the bottom of Fig. 1 but with parts broken away to more clearly show the construction;

Fig. 3 is a section substantially on line 3-3 of Fig. 1;

Fig. 4 is a view similar to Fig. 1 but showing the switch in off position;

Fig. 5 is a side elevation of the switch on a reduced scale;

Fig. 6 is a perspective view of one of the end members or end plate of the frame or housing;

Fig. 7 is a detail section substantially on line 7-7 of Fig. 1;

Fig. 8 is a section looking from the right of Fig. 7;

Fig. 9 is a perspective view of the spring rocker plate;

Fig. 10 is a perspective view of the nut or clamp used in mounting one of the switch contact members;

Fig. 11 is a perspective view of the movable switch member or assembly;

Fig. 12 is a perspective view of one end portion thereof with the switch contacts removed;

Fig. 13 is a perspective view of one of the switch contacts, and

Fig. 14- is a wiring diagram illustrating one use of the switch.

The switch comprises a housing or frame 1 made of two end members or plates 2 connected by opposite laterally spaced side plates 3. The end members or plates are of metal, while the side plates 3 are of electrically insulating material, such, for example, as phenolic condensation plastic material on a cloth base, one form of Patented ,Mar. 26, 1957 which is commonly known as Micarta. The end memhere 2 each comprise an upright intermediate connecting wall 4 and parallel laterally spaced upright flanges 5 at substantially right angles thereto and to the outer sides of which are secured the side plates 3 by any suitable means, such, for example, as the screws 6. The connecting walls 4 of the end members are provided with openings '7 for a purpose later to be described, and the top portion of these walls are bent inwardly, as shown at 8, and then downwardly as shown at 9, to provide stop walls to limit the opposite movements of the movable switch member, as will also later be described. At their upper ends the side flanges 5 are provided with outwardly extending lugs or ears 10 to which the cover plate 11 is secured by any suitable means, such, for example, as the screws 12.

The movable switch member or assembly comprises two laterally spaced handle members or switch contact supports 1.3 in the form of insulating plates which are also of electrical insulating material and may be made of the Micarta or cloth base phenolic material. They each comprise a substantially circular main or body portion 14 and an extension or handle portion 15, and they are mounted in lateral spaced relation on a central pivot or shaft 16 mounted at its opposite ends in bearings 17 in the side plates 3 of the housing or frame and secured by any suitable means, such, for example, as the nuts 18 threaded on the opposite ends of the shaft. The portion 19 of the shaft between the bearings is knurled, as shown in Fig. 3, to hold the switch members 13, and these switch members are retained in suitable spaced relation by an intermediate spacer or sleeve 23 on the shaft and in proper spaced relation from the side plates 3 of the housing by similar spacers or sleeves 21. These spacers are of suitable material, preferably light-weight material such, for example, as aluminum. This shaft 19, therefore, mounts the movable switch assembly, including the members 13 and the elements carried thereby, for rocking movement between the side plates 3 of the housing in opening and closing the circuits, as will presently be described.

Mounted on and carried by these members 13 are two bridging contacts comprising a contact pin 22 and a substantially U-shaped contact 23. The contact 22, as indicated, comprises a transverse pin of brass or similar conducting material mounted at its opposite ends in openings 24 (Fig. 12) through the plates 13, and it is retained in these members by a flange 25 and washer 26, the opposite ends of the pin projecting, as shown at 27 (Figs. 2 and 11) beyond the plates to engage the stationary electrical contacts 28 mounted on the inner side of the side plates 3 of the housing. A spacer in the form of an insulating sleeve 29 of fiber or other suitable material is on the pin 22 between the members 13.

The stationary contacts 28 are spring contacts having a resilient contact portion of arc shape 30, a perspective view of one of these contacts being shown in Fig. 13, the curved or arc shaped portion 30 being offset at 31 from a head or base 32 provided with a square or noncircular opening 33 to receive a similarly shaped neck 34 on a mounting screw or stud 35, this stud including a suitable enlarged head 36 on the inner side of the base 32 of the contact. The squared or noncircular neck 34 of the stud is seated in the similarly shaped opening in the side plate 3 whereby it is held against turning, and the stud has a threaded shank 37 on the outside for receiving a binding nut 38 for clamping a lead wire connector 39 between it and a washer 40 for electrical connection with the contact 28. There is one of these contacts on each of the side plates 3, as shown in Figs. 2 and 3, and the contacts are the same except they are right and left hand to be engaged by the opposite ends 27 of the contact pin 22 which therefore in this position bridges the contacts 28. The free ends of the contacts 28 may be offset or bent laterally, as shown at 41, to facilitate the entrance of the opposite ends of the pin 22 to a position between the contacts 28.

Also carried by the movable switch members 13 is the substantially U-shaped contact 23 as above indicated, this contact being spaced from the contact pin 22 and mounted on lateral extensions or lugs 32 formed on one side of the circular body portions 14 of the members 3. These lugs, as shown in Fig. 12, are each provided wi or recess 4-3 in their outer edges, the two g "r-- ment, and inwardly of these recesses are substantially T-shaped openings 44 with the narrower portions 45 of these openings extending toward the notches 43. contact 23 comprises a transverse connecting cc-d3 46 and side members or legs 47 at substantially Lght Cngles thereto forming contact portions. The trans rs: connecting portions 46 seats in thc notches 43 with the contact portions 47 on the outer sides of the two plate members 13.

These contact portions 47 are w rcct or extended by curved extensions 43 to engage and bridge the heads 49 (Figs. 2 and 3) of stationary contact studs 50 mounted in side plates 3 of the housing. These studs each have a square or noncircular neck 52 seated in a similarly shaped opening in the plate 3 to keep them from turning, and they are secured in the plate by a suitable nut 52 on the threaded shank 53 of the stud. This nut and shank are also used to mount a binding plate 54, the square neck 51 being of a length to also extend through a similarly shaped opening in this member This plate is provided with an inwardly extending lug on one edge to seat in a similarly shaped elongated opening 545 in the plate 3 to serve as a further means to hold the plate 54 against turning. This plate also has laterally and outwardly extending lugs 55 at its opposite side edges to receive between them the head 56 of a battery connector 57 to hold this connector against turning movements on the stud, and when this connector head is clamped between the plate 54 and the nut 52 to form an electrical connection from a conductor or batter cable 555 with the stud S0.

The contact 23 is mounted and retained in the notches 43 by means of a nut or clamp 59 (shown in detail in Fig, 10) in the shape of a plate which has a T-shaped head 60 at its opposite ends. These heads may pass through the wider portions of the T-shaped openings 44 and then the reduced neck 61 may seat in the narrower portion 45 of the openings 44, and be secured therein by means of a screw 62 passing through an opening in the connecting portion 46 of the contact 23 and threaded into a tapped opening 63 in the nut 59. The contact 23 is also secured in position in the notches 43 by this screw. To prevent the screw from loosening and dropping out it may be secured by a wire or any suitable means 64. The contact 23 is, however, not a close fit in the recesses 43, so that it is free to adjust itself or find its proper position in its supporting members and between the two sta ionary contacts 49. Also this contact 23 is not a spring contact but is a substantially solid member, there being sufficient spring or resiliency in the supporting insulating plates 13 and 3 for the contact to properly center itself between the stationary contacts 4-9 and have uniform contact or pressure with these contacts.

Means is provided for yieldingly retaining the movable switch assembly comprising the supporting members i3 and the bridging contact elements carried thereby in either the on position of Fig. l or the off position of Fig. 4. For this purpose the body portions 14 of tie members 13 are provided with inwardly extending recesses or notches 65 in the diametrically opposite side from the notches 43 and the contact 23, and mounted in these notches is a rocker stud 66, it being secured therein by any suitable means, such, for example, as a flanged head 67 and a washer 68 forced on the reduced end of the stud. This stud forms a pivot support for a toggle link 69 comprising a fiat strip including a shank 70 and a widened head 71 wrapped around the stud 66. Mounted on the shank 70 is a coil compression spring 72 resting at its inner end against a washer 73 on the shank and at its opposite end against a spring rocker plate 74 (shown in detail in Fig. 9). This plate has a central elongated opening 75 through which the shank 79 extends and has sliding movement, and at its opposite edge is provided with laterally extending lugs 76 to assist in retaining the end of the spring in engagement with the plate. This plate is mounted for limiting rocking movement in one of the end walls 2 of the housing. For this purpose the flanges 5 of this end wall, as shown in Fig. 6, are provided with notches 77 to receive the lugs 78 of spring rocker bearings 79 (Figs. 6 and 7), These bearings are each in the form of a plate of substantially L shape and each has a lug Sit on its outer edge passing through an opening 81 in the connecting wall 4 of the member 2, and is then riveted over as shown at 82 to secure the plate in position. The rocker plate 74 seats at its opposite ends on the shoulders 83 of these plates with the edge 34 of the plates seating in notches 85 in the ends of the members '74-, and these notches are somewhat wider than it e thickness of the plates 79 to permit limited rocking movement of the plate 74. These plates 79 are mounted on opposite sides of the opening 7 in the end member 2 to permit passage of the free end of the toggle link 69.

These supporting plates 79 and the rocker plate 7- are located, as shown in Figs. 1 and 4, in substantially horizontal alignment with the supporting shaft 16 for the movable switch assembly. Therefore, as this asscmbly, including the contact bridging members 13 and 22, is rocked back and forth between the on position of Fig. l and the off position of Fig. 4, the toggle pin or stud 66 is shifted across the line joining the center of the shaft 16 and the supporting plates 79 compressing the spring as the stud 66 moves from either side toward this line, and then after it passes this line the spring expands and snaps the movable assembly to the opposite position, providing a toggle action for operating the movable switch assembly. The movements of the members 13 are limited by the stop walls 9 on the end members 2 of the housing or supporting frame. The free outer ends of the members 13 are connected by a spacing nut 86 of some suitable material, such, for example, as hard fiber, having tapped holes in its opposite ends to receive the screws 87 passed through the free ends of the members 15, and this nut is enclosed in a sleeve 88 of aluminum or similar material forming a bearing connection for some operating means (not shown) such, for example, as a cable or some other means for remote control and operation of the switch. The cover plate 11 is provided with a pair of longitudinal slots 89 through which the handle members 15 extend.

A wiring diagram indicating a use of this control switch is shown in Fig. 14, wherein the contacts 28 and the bridging contact pin 22 are in the charging circuit from the generator 9%) to the battery 91, and the stationary contacts 49 and the bridging contact 23 are in the battery circuit with the starter, lights, instruments, and so forth indicated by the broken line rectangle 92. It will therefore be seen that both these circuits are controlled simultaneously by this switch, or that is, both the battery circuit and the generator circuit are made or broken at the same time by operation of this switch between its on and off positions of Figs. 1 and 4. This may be used as the main switch for controlling the source of current in both circuits on an airplane, for example, and if trouble should be experienced as, for instance, fire starts somewhere on the plane, the battery and the high tension systems, generator and so forth, may be immediately isolated by throwing of this switch to thus avoid possible spread of the fire.

It will be seen from the above that this construction and arrangement of the parts of the switch provides a light-weight construction, and also that there are no molded insulating parts as are commonly used in electrical switches.

Having thus set forth the nature of my invention, I claim:

1. A safety switch comprising a housing including laterally spaced parallel insulating frame plates, separate end members extending between and connecting said plates, two pairs of aligned stationary contacts mounted on said plates, means mounted on the plates for connecting conductor wires to said contacts, a movable switch assembly mounted between said frame plates comprising a pair of laterally spaced supporting plates, a shaft extending between and supporting said latter plates and having bearings at its opposite ends in the frame plates, 21 pair of transversely extending bridging contacts mounted in the supporting plates and each movable with these plates to and from positions between and bridging the respective pairs of stationary contacts for making and breaking circuits including the stationary contacts, and means for shifting the switch assembly between the circuit making and breaking positions and retaining it in these positions.

2. A safety switch comprising a housing including laterally spaced parallel insulating frame plates, separate end plates extending between and provided with opposite edge flanges connected to said frame plates, stationary contacts mounted one on each of said frame plates, means mounted on the frame plates for connecting a conductor wire to each contact, a movable switch assembly mounted between said frame plates comprising a pair of laterally spaced insulating plates, a transverse shaft on which the latter plates are mounted and supported at its opposite ends in the first plates, a bridging contact mounted on the switch assembly plates and movable with these plates to and from a position between and bridging the stationary contacts for making and breaking a circuit including said contacts, and operating means for shifting the switch assembly between the circuit making and breaking positions and retaining it therein.

3. A safety switch comprising a housing including laterally spaced side plates, separate end plates extending between and connected to the side plates, stationary contacts mounted one on each of the side plates, means mounted on the plates for connecting a conductor wire to each contact, a movable switch assembly mounted in the housing comprising a pair of spaced insulating plates each including a body portion and a laterally extending handle portion, a transverse shaft extending between and mounting said body portions and supported at its opposite ends in the side plates, a bridging contact mounted on said insulating plates and movable therewith to and from a position engaging and bridging the stationary contacts for making and breaking a circuit including said contacts, and said handle portions forming means whereby said switch assembly may be shifted between the circuit making and breaking positions.

4. A safety switch comprising a housing including laterally spaced side plates, end plates extending between and connected to the side plates, stationary contacts mounted one on each of the side plates, means for connecting a conductor wire to each contact, a movable switch assembly mounted in the housing comprising a pair of spaced insulating plates each including a body portion, a transverse shaft extending between and mounting said body portions and supported at its opposite ends in the side plates, said body portions of the insulating plates provided with aligned recesses in one edge and an opening through each plate spaced inwardly from the recess, a bridging contact having spaced contact portions to engage the stationary contacts and a connecting portion seated in said recesses, a nut supported at its opposite ends in said openings, a screw connecting the nut and said connecting portion to retain this contact in the recesses, and means for operating the switch assembly to shift the bridging contact to and from engagement with the stationary contacts.

5. A safety switch comprising a housing including laterally spaced side plates, stationary contacts mounted one on each of said plates, means for connecting a conductor wire to each contact, a movable switch assembly within the housing comprising a pair of insulating plates each including a body portion and a laterally extending handle portion, a transverse shaft extending between and mounting the body portions and supported at its opposite ends in the side plates, said body portions being provided with aligned notches in their edges and openings through the plates spaced inwardly of said notches, a bridging contact including a transverse member seated in said notches and end members to engage the stationary contacts, a securing member comprising a nut seatedat its opposite ends in said openings, a connecting screw extending between the transverse member and the nut, and means whereby operating means may be connected to the handle portions for operating the switch assembly to shift the bridging contact to and from engagement with the stationary contacts.

6. A safety switch comprising a housing including laterally spaced side plates, stationary contacts mounted one on each of said plates, means for connecing a conductor wire to each contact, a movable switch assembly within the housing comprising a pair of insulating plates each including a body portion, a transverse shaft extending between and mounting the body portions and supported at its opposite ends in the side plates, said body portions being provided with aligned notches in their edges and substantially T-shaped openings spaced inwardly from the notches with the narrower parts of said openings extending toward the notches, a bridging contact including a transverse member seated in said notches and end members to engage the stationary contacts, a securing member comrising a nut in the form of a plate having substantially T-shaped ends seating in the narrower portions of said openings, a securing screw connecting said nut and the transverse portion of the bridging contact to retain said contact in the recesses, and operating means for the switch assembly to shift the bridging contact to and from engagement with the stationary contacts.

7. A safety switch comprising a housing including a pair of laterally spaced insulating side plates, a plurality of pairs of opposed stationary contacts mounted on the side plates, means mounted on the side plates for connecting a conductor wire to each contact, a movable switch assembly within the housing comprising a pair of insulating plates each including a body portion and a laterally extending handle portion, a transverse shaft extending between and mounting the body portions and supported at its opposite ends in the side plates, a pair of spaced bridging contacts carried by said body portions and each movable to and from engagement with a given pair of said stationary contacts to control circuits including said contacts, and said handle portions forming operating means for the switch assembly to shift the bridging contacts to and from engagement with the respective pairs of stationary contacts.

8. A safety switch comprising a housing including a pair of laterally spaced insulating side plates having noncircular openings, a stationary contact for each plate comprising an enlarged head at the inner side of the plate, a noncircular neck seated in said opening and a threaded outer shank, a binding plate having a similarly shaped noncircular opening on said neck and having an inwardly extending lug at one edge seated in a recess in the plate and outwardly extending lugs on opposite side edge to receive a conductor wire connector be tween them, a clamping nut on the threaded shank adapt ed to clamp the connector to the binding plate between the outwardly extending lugs, a movable switch assembly in the housing comprising a transverse shaft mounted at its opposite ends in the side plates, a supporting means mounted on the shaft, a transverse bridging contact mounted on said supporting means and movable therewith to and from engagement with the stationary contacts, and means for operating the switch assembly to shift said bridging contact to and from engagement with the stationary contacts.

9. A safety switch comprising a housing including a pair of laterally spaced insulating side plates having noncircular openings, a stationary contact for each plate comprising a spring member including a base having a noncircular opening and a laterally offset resilient contact engaging portion, a mounting stud including an en larged head and a. noncircular neck portion in said non circular openings in the contact member and the insulating plate, said stud having a threaded outer end portion, a clamping nut on said outer portion for clamping a lead wire connection to said stud, a movable switch assembly in the housing comprising a transverse shaft mounted at its opposite ends in the side plates, a supporting means mounted on the shaft, a transverse bridging contact mounted on said supporting means and movable therewith to and from engagement with the stationary contacts, and means for operating the switch assembly to shift said bridging contact to and from engagement with the stationary contacts.

10. A safety switch comprising a housing including laterally spaced side plates, end plates extending between and connected to the side plates, stationary contacts mounted one on each of the side plates, means for connecting a conductor wire to each contact, a movable switch assembly mounted in the housing comprising a pair of spaced insulating plates each including a body portion and a laterally extending handle portion, a transverse shaft extending between and mounting said body portions and supported at its opposite ends in the side plates, a bridging contact mounted on said insulating plates and movable therewith to and from a position engaging and bridging the stationary contacts for making and breaking a circuit including said contacts, said body portions provided with aligned notches in one edge, a rocker stud seated in said notches, a spring rocker plate mounted for limited rocking movement on one of the end plates and provided with an opening, a toggle link including a shank connected at one end to said stud and at its other end slidable in said opening, a coiled spring on the shank between the stud and the rocker plate, and said handle portions providing means whereby said switch assembly may be shifted on said shaft as a pivot to carry the bridging contact to and from engagement with the stationary contacts and pass the rocker stud across the line joining said shaft and the rocker plate for a toggle action to rapidly shift the switch assembly in opposite directions.

11. A safety switch comprising a housing including laterally spaced side plates, end plates extending between the side plates and including side flanges at the inner sides of the side plates connected thereto, the flanges of one of said plates provided with transverse slots leading from their inner edges, stationary contacts on the side plates, means for connecting conductor wires to said contacts, a movable switch assembly mounted in the housing including spaced supporting plates, a. pivot shaft supporting said plates mounted at its opposite ends in the side plates, a toggle link including a head at one end pivotally mounted in the supporting plates, a pair of spaced spring rocker bearing plates mounted in said notches in the flanges of the end plate and having notched opposed inner edges forming shoulders, a spring rocker plate seated on said shoulders and having notches in its opposite ends embracing said inner edges, said rocker plate also provided with an opening, said toggle link including a shank in said opening, a spring on said shank between the rocker plate and the head of said link, a bridging contact on the supporting plates movable with these plates to and from engagement with the stationary contacts, and means for operating the movable switch assembly.

References Cited in the file of this patent UNITED STATES PATENTS 2,158,369 Jackson May 16, 1939 2,506,987 Becwar May 9, 1950 2,538,581 Minch et a1. Jan. 16, 1951 2,614,186 Sutton et a1. Oct. 14, 1952 FOREIGN PATENTS 821,662 France Aug. 30, 1937 

